Method of and apparatus for edgegluing veneer sheets



A. R. WELCH July 25, 1950 METHOD OF AND APPARATUS FOR EDGE-GLUING VENEER SHEETS Filed Nov. 8, 1944 2 2 0 7E ev e F f 9 3mm.- tflz m ramzch,

Patented July 25,1950

U I ED;seq-Ar s PATENT OFFICE METHODOFAND APPARATUS FOR EDGE- GLUINGVENEER SHEETS 1 Arthur It. Welch, Aberdeen, Wash. Application November 8,1944, Serial No. 562,499

Claims. (01. 154-116) -=The present inventionrelates to the -plywood art and, more particularly-, toan improved method of and apparatus for edge-gluing woodplies or veneer strips or sheets. gIn-the-manufacture of plywood under present may conditions, it is seldom, if ever, possible to procure unblemished face plies of-the'full width of the panel's which it is desired to produce) Itis a common practice, to cut from larger sheets, or-' the elongated ribbon peeled from the log, those-portions which are defective, for instance, because of the presence of knots, pitch pockets, checks; cracks or the like. The intermediate, non-defective portions are of varying width and are assembled to provide face plies, or face and back-:plies,-by edge-gluing the strips or-sheets, to build upveneer'plies of the proper width. The individual strip or sheets, in some cases, are patched or otherwise treated, before or after edge gluing,'-"to remove minor defects, but the gluing of the edges of the individual strips has always been a laborious, time-consuming and expensive procedure; In some cases the glue has been applied to the edges of the sheets byhand, whilein other cases, complicated and expensive machineshave been used, all with indifferent success. One Well-known type of machine attempts to apply'glue to the converging edges of adjacent wood p ies moving along a table or other support under the influence of conveyors, bym'eans-of 'a rotating disc which dips 'into aglue reservoir 'and carries the glue upwardlyby surface tension ahdapplies'the glue by a wiping-action to one or both edges of the adjacent strips. Trouble has been encountered with machines of thiski'ndghowever, because the amount of glue applied varies considerably with varying conditions and an excess of glue tends to build up on the disc'with the result that accurate control is impossible. Ifan-excess of glue is applied to the edges, it is*sqi 1eezed'out ofthe jOint-under the infiuence'of lateral gluing pressure and the table and conveyors'become 'sm'earecl' with glue, with the resultthat-"the-surfaces of the plies are stained and marred, leaving a coating of glue on the face of the-finished product andgaps are produced;

The presentinvention aims toovercome all of the defects of sucli'priorme'thods andnia'chines The prima ry object 'of 'the ln vefitioifis 13C) "provide a new method of and apparatus for applying to the edges of wood plies an accurately controlled amount of glue which will be evenly distributed throughout the joint and which will not become deposited upon any parts of the machine or smeared upon the surfaces of the finished product.

A further object of the invention is to provide a method of and apparatus for edge-gluing in which a reinforcing element, preferably in the form of a textile thread, is deposited in the joint to form a permanent part thereof. r A further object of the invention is to produce an improved joint by depositing exactly the correct amount of adhesive between the edges to be glued, taking into account the thickness of the plies and, hence, the area to be glued, the nature of the wood, the characteristics of the adhesive and other variable factors.

A further object of the invention is to provide a method of and apparatus for edge-gluing wood plies in accordance with which the time required to produce a tight and permanent joint may be materially reduced.

Other and further objects and advantages of the invention will be apparent to those skilled in the art from a consideration of the specific embodiment of the invention shown for purposes of illustration in the accompanying drawings and described below.

In the drawings,

Figure 1 is a fragmentary plan view of one" form of apparatus, with certain parts removed;

Figure 2 is a longitudinal section, with certain parts shown in elevation, of the apparatus of 3 Figure 1;

Figure 3 is a transverse section of Figure 2,

taken substantially on line 3-3 thereof.

Figure 4 is an enlarged cross-sectional view plied and;

Figure 5 is a cross section through the finished joint.

Pairs of veneer strips [0 and II, of any desired width are adapted to be fed forwardly, toward the left in Figures 1 and 2 over a table or other support l2 having a plane upper surface I3. As

in conventional practice, the edges l4 and I5;

which are to be adhesively united, are first milled square so that they lie in parallel, vertical planes. The veneer strips or sheets are fed by hand or by suitable conveying means, not shown, along converging lines past a spacer orseparator blade IB, positioned above the table, to prevent premature contact of the edges. The strips are fed 2,c1c,2so a onto the upper surfaces of a pair of converging conveyor belts l1, l8, trained about rear pulleys I9 and 20 and forward pulleys 2|, 22, either or both pairs of which may be positively driven by any suitable means, not shown. The belts may be made of any suitable material, such as woven, rubber-surfaced belting of commerce. A similar pair of upper belts, one of which is shown in Figure 2 gat26 may be employed, as hold-down belts and toassist' in the advancing-and converging of the strips. The upper belts preferably lie directly above the lower ones and are disposed in similar angular relation. As indicated in Figure 2, the belt 26 has its lower, strip engaging run disposed beneath a plurality of guide rollers 2! which may be urged downwardly by spring means or the like, to maintain the belt firmly in contact with the veneer sheets. Theforw ardly and rear wardly disposed pulleys 29, 38, about which Ithe upper belts are trained are preferably positively driven, although they may be idler pulleys, if desired. v

The edges of the strips or sheets of veneer H], H move on converging lines from a spaced-apart point 35, immediately ahead of the spacer blade It, to a bite .36 and then along a line of edge contact under the influenceof advancing and converging pressure applied to the sheets or strips by the lower belts IT, IS and the upper belts 26. The sheets or strips are relatively thin and have sufiicient lateral flexibility to permit this converging of their edges. As the strips or sheets leave the belts, the joint may pass between and in contact with one or more heating elements represented diagrammatically at 40, 4] which may be disposed above and/or below the sheets, in contact therewith, to accelerate the setting of the adhesive applied to the joint, by means now to be described.

Beneath the table l2 and substantially in vertical alignment with the spacer blade Hi, there is an adhesive reservoir ,45, supported in any suitable manner, as, for instance, by a bracket 46 secured to the under surface of the table :and having arms 41 adapted to engage the closure 48, for the receptacle. The closure may carry a pair of depending arms 49, 59, upon which there ismounted a roller 5| by means of a transverse pin or shaft 52. The cover is also. fitted with a delivery guide tube 53 and an entrancetube 54, the former being aligned with an opening 55 in the table, just ahead of the spacer blade 16 and the latter being turned rearwardly toward a source of supply of thread or the like, which may conveniently be in the form of a spool or cheese 56 mounted forrotation on a spindle 5'], The guide tube 53 may extend upwardly through the hole 55 to a pointabout of an inch above the surface l 3 of the table i2, or a projection 58 having agroove in its upper surface may be employed to lay the thread midway between the upper and lower, faces of the veneer strips.

The thread 60 may be of any suitable type, so

long, at it is capable of performing its intended function. A relatively light cotton textile thread serves Welland may be obtained at a reasonable price from any source. Such a thread, unwound from the spool 55 is guided through the tube .54, beneath the surface of the glue 5!! in the pot .45, under the roller 51 and upwardly through the discharge tube 53 and through the opening-55 in the table. The leading end of the thread is placed in the bite between the converging edges; of the veneer strips 'and- I L'TThe thread, after passing through the adhesive in the Dot carries edges, as the edges converge and move forwardly.

comes a permanent part of the joint. heaters 40, Msufficiently set the adhesive to pre- The threadis-continuously drawn upwardly and applied to'the edges and advances with the forwardly moving and converging strips and be- The vent accidental separation of the plies. Final setting may occur under atmospheric temperatures and without the application of further t ral ipressurc. but in some cases, as, for instance,when-fasmsettineadhesives, Such as ureaformaldehyde resins are used, final conversion of the resins.ancL-hence, final setting of the adhesive may occur under the influence .of the-heat appliediby the heaters 40,41.

Figures-4 .and.:5 indicatethe action of the converging pressure, tending .to .flatten the thread and to squeeze-the glue throughout substantially the entire area of the joint. N

,If it is desired in some cases to re-use the thread, itmaybe pulled out of theioint, after a predetermined amount of lateral converging pressure has been applied to the veneer strips. Inthi s case, the major-portion of the glue will have beentransferred to the edge facesby the quee ga tion, and he thread mayb continuously withdrawn as the veneer sheets move along. The thread'maybetreatedto remove the residueuof adhesive, as by washing or cleaning. and then wound up for re-use, or, if'desired, it may be led directly to the-glue pot for passage therethrough and for r e-insertion into the Joint then moving above the table. If the latter. procedure .isfollowed, it is more satisfactory to use anendless metallic wire of thin section and to lead the .wire directly back to the glue pot, where itpicks up a newsupply ofglue andthen to reinsert the-wire into the-joint, and so on.

However, in most cases itis preferred to-leave the threadinthe joint as-a permanent part thereof, to -act as a, reinforcing element and as means to efiectively distribute the glue over'the surfaces to-be joined, assisting in compensating for irregularities the edge faces and .the like.

The term thread in the accompanying. claims is used in .its broadest sense and: is intended .to cover any andalirelatively long strands, such as yarn, filaments, cordsstring, strips, tapes, lines, wires and the like. 7

It mustbe-understood that the invention .is not limitedto-the details of constructionof the apparatus shown inthe accompanying drawings and described above, nor to theprecise method steps indicated-as, preferred, but contemplates, such changes-andmodifications as will occur .to those skilled. in the artzfrom a consideration of t specification. All such changes as -.come.

1. The method of edge-gluing woodplies which.

omprises ont uously feeding the lies with their: edges to lie-glued .J'uxtapos d ins de by side.

relation, continuously andprogressiveiy delivering anadhesively coated thread between said edges,-i.progressively pressing: the iiedgestogether with the thread. therebetween -andLthereby transferring'the adhesive to the edges to adhesively unite the'same. i 2. The method of edge-gluing'wood plies which comprises simultaneously moving the adjacent edges of a pair of plies on converging paths from a spaced-apart point to a bite and a continuing line of contact, feeding an adhesively treated thread into the bite and continuously depositing the same therebetween as the edges move along said line of contact, transferring the adhesive to the edges, and continuously and progressively setting the adhesive to unite the edges.

3. The method of edge-gluing wood plies which comprises simultaneously moving the adjacent edges of a pair of plies n converging paths from a spaced-apart point to a bite and an advancing line of contact, continuously feeding a thread from a source of supply to the bite between the edges, continuously applying adhesive to said thread ahead of the bite, thereby depositing the thread and the adhesive between the edges as they move along said line of contact, and setting the adhesive on the edges to adhesively unite the plies.

4. The method of edge-gluing wood plies which comprises simultaneously moving the adjacent edges of a pair of plies on converging paths from a spaced-apart point to a bite and a subsequent line of contact, inserting the end of a thread into the bite between the edges, drawing the thread from a source of supply, continuously depositing the same between the edges as the plies move along said path, continuously guiding the thread ahead of the bite through a supply of adhesive, whereby the thread deposits adhesive upon the edges to be glued, and setting the adhesive to unite the edges.

5. The method of edge-gluing wood plies which comprises simultaneously moving the adjacent edges of a pair of plies on converging paths from a spaced-apart point to a bite and a subsequent line of contact, inserting the end of a thread into the bite between the edges, drawing the thread from a source of supply, continuously depositing the same between the edges as the plies move along said path, continuously applying adhesive material to the thread ahead of the bite, where-- by the thread deposits the adhesive between the edges, and setting the adhesive in that position to unite the plies.

6. In an apparatus for edge-gluing wood plies having means for simultaneously moving a pair of plies along predetermined paths such that their edges to be glued follow converging lines from a fixed, spaced-apart point to a line of contact extending from a bite positioned at a substantially fixed point, means for applying adhesive to said edges, said means comprising means for holding a supply of thread, an adhesive supply, and means for guiding the thread through the adhesive supply to the bite between the edges to be glued.

7. In an apparatus for edge-gluing wood plies having means for moving a pair of plies along predetermined paths with their edges converging from a spaced-apart point to a bite and a line of contact, said means serving to apply lateral pressure to the edges; means for continuously applying adhesive to the edges, and means for accelerating the setting of the adhesive, said adhesive applying means comprising means for guiding an adhesively treated thread and for depositing the same in the bite between :the edges.

8. In an apparatus for edge-gluing wood plies having atable over which theplies are adapted to be moved, converging conveyor means adapted to engage the surfaces of adjacent plies and to convey them along lines froma point wherethe edges .are spaced-apart to a bite and along a line of, edge contact and to apply lateral converging pressure to the edges, and spacer means p ositioned between the lines of movement of the plies to prevent premature contact of 'the edges; means for applying adhesive 'to said edges, said means comprising means for continuously delivering to the bite between the converging edgeslof ithe plies an adhesively treated thread, whereljythe thread is drawn forwardly with the movement of the plies and deposits adhesive between said edges.

9. In an apparatus for edge-gluing wood plies having a table over which the plies are adapted to be moved, a pair of converging conveyors on the surface of the table adapted to engage the under surfaces of adjacent plies and to convey them along lines from a point where the edges are spaced-apart to a bite and along a line of edge contact and to simultaneously apply lateral converging pressure to the edges, means above the table for urging the plies downwardly into contact with said conveyors, and spacer means positioned between the converging edges of the plies to prevent premature contact thereof; means for applying adhesive to said edges, said means comprising means for delivering an adhesively treated thread upwardly through the table to the bite between the converging edges of the plies, whereby the thread is drawn forwardly with the movement of the plies and deposits adhesive between the edges thereof.

10. In an apparatus for edge-gluing wood plies having a table over which the plies are adapted to be moved, a pair of converging conveyors on the surface of the table adapted to engage the under surfaces of adjacent pliesv and to convey them along lines from a point where the edges are spaced-apart to a bite and along a line of edge contact and to simultaneously apply lateral converging pressure to the edges, means above' the table for urging the plies downwardly into contact with said conveyors, and spacer means positioned between the converging edges of the plies to prevent premature contact thereof; means for applying adhesive to said edges, said means comprising a receptacle for liquid adhesive below the table, means for guiding a thread from a source of supply through the receptacle and for guiding the same upwardly through the table into the bite between the converging edges of the plies, whereby the thread andadhesive there-' on are drawn forwardly with the movement of the plies and the adhesive is deposited between said edges, and means for setting the adhesive while the edges are subjected to said lateral converging pressure.

ARTHUR R. WELCI-I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 21,593 Friz Oct. 8, 1940 558,827 Morris Apr. 21, 1896 712,794 Hill Nov. 4, 1902 (Other references on following page) 

